Stacking stool



FIG. 1 is an isometric view of a stacking stool according to our new design, generally from an upper angle;

FIG. 2 is front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right side view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The broken lines in the drawings depict portions of the stool that form no part of the claimed design. 

CLAIM The ornamental design for a stacking stool, as shown and described. 